1. Field of the Invention
The present invention relates to an electronic apparatus including a rotational operation member formed in two tiers.
2. Description of the Related Art
Conventionally, there has been a rotational operation mechanism mounted on an electronic apparatus such as a camera. In the rotational operation mechanism of this type, a mechanism for allowing an upper dial (rotational operation member) and a lower dial (rotational operation member), which are formed in two tiers, to independently rotate about 360 degrees from each other is not put to practical use because of restrictions in size and strength.
Techniques explained below are proposed concerning the rotational operation mechanism. For example, Japanese Laid-Open Patent Publication (Kokai) No. 2002-165124 discloses a rotational operation mechanism in which a diameter of an upper rotational operation member is smaller than a diameter of a lower rotational operation member.
For example, Japanese Laid-Open Patent Publication (Kokai) No. 2002-165123 discloses a rotational operation mechanism in which a rotation angle of an upper rotational operation member is larger than a rotation angle of a lower rotational operation member.
For example, Japanese Laid-Open Patent Publication (Kokai) No. H9-5814 discloses a second rotational operation member that is disposed to overlap a first rotational operation member in a rotation axis direction and can be rotated independently from the first rotational operation member. Further, Japanese Laid-Open Patent Publication (Kokai) No. H9-5814 discloses a lock member that is attached to the second rotational operation member and moved in a radial direction of the second rotational operation member between a lock position for preventing rotation of the second rotational operation member and an unlock position for releasing the prevention of the rotation. In the technique disclosed in Japanese Laid-Open Patent Publication (Kokai) No. H9-5814, the second rotational operation member located below the first rotational operation member cannot rotate 360 degrees. Therefore, the technique is different from an embodiment of the present invention explained later.
In the above described prior art, there exists following problems. As explained above, since the rotational operation mechanism for allowing the upper and lower rotational operation members to independently rotate about 360 degrees from each other in a camera is not put to practical use, restriction in use and heavy stress are imposed on a user.
There is a limit in the number of modes that can be arranged on each of the rotational operation members (the number of modes that the user can select). This limit also restricts design of the rotational operation mechanism. Further, since indicators are respectively arranged on the rotational operation members, kinds of indicators increase. Therefore, visibility is not satisfactory for the user. The rotational operation members are complicated in design.
Springs for creating a feeling of click of the rotational operation members are made of tabular members. Therefore, when a torque of the rotational operation members is changed or adjusted and when the rotational operation members are assembled, cost increases as well as work processes increase.
A space between the rotational operation members is small. The rotational operation members are remote from a component set at a ground (GND) level on a camera main body side. Therefore, when the rotational operation members are made of metal, it is difficult to perform ground connection for protecting the camera from electrostatic destruction.